A new study of algae polluting Lake Erie indicates that some farming practices are encouraging the spread of algae. The authors of the study also point to the lack of data to analyze all aspects of the most polluted pollution of the five Great Lakes.
According to the study of the International Joint Commission (IJC), the Canada-US organization that studies and manages the freshwater areas shared by both countries, some trends in fertilizer application that have been used for more than ten years are encouraging for the western basin of the lake.
“Phosphate fertilizer ratios are decreasing while phosphorus removal by crops has increased […] without harming crops,” reads the conclusion.
Over the years, a number of experts have shown that fertilizer phosphorus used by Canadian and American farmers has, in large part, caused the growth of algae in Lake Erie.
Ontario, Michigan and Ohio agreed in 2015 to achieve a 40% reduction in high-phosphorus runoff until 2025.
“I think it’s a good study, but (that’s) only a small part of the puzzle,” Jerome Marty, president of the Canadian Society of Limnology, Freshwater Science, said in a telephone conversation.
Lack of data
The authors of the study repeatedly point out in the report the difficulty of obtaining data on the two main agricultural sources of phosphorus in the lake, that is, manure and chemical fertilizer.
“One of the big difficulties in understanding this is the transport of these sources, we need more studies on a larger spatial scale,” says Marty.
The authors also believe that longer-term studies are needed to understand the dynamics of Lake Erie’s sources of phosphorus.
According to them, these research programs should also be financially secure and not at the mercy of a newly elected politician.
In the study, the authors convert the annual value of fertilizer and manure on agricultural land to indicate the phosphorus intake of both countries in Lake Erie water.
Based on the most recent binational data from 2006-2007, 72% of phosphorus would be released into the US basin of the lake and 28% into the Canadian portion of the lake.
Some members of the National Farmers Union (NFU) in Ontario reject this data.
“It worries me. How much data that is 11-12 years old is relevant to the current situation? Said UNF’s Don Ciparis aloud during a public online video conference on Tuesday.
He argues that Canadian farmers raise less livestock and favor crops because of market prices.
The authors of the study, David Allan and Michael Murray, defend the use of these data.
“This is the most recent data […] and I think it’s relevant because we’re looking at long-term trends,” argues Murray.